Duplex quantum invisible state transmission device

Abstract

The invention belongs to the technical field of quantum information science, and particularly relates to a duplex quantum teleportation device. The system comprises a first user node, a second user node and a server node, the user node is provided with a quantum information sending module and a quantum information receiving module, the quantum information sending module is used for quantum information, and the quantum information receiving module recovers a transmitted quantum state according to a Bell state measurement result. The server node receives quantum information sent by the user node and performs Bell state measurement, records and sends each Bell state measurement event to the user node, and distributes signal photons corresponding to idle frequency photons to the user node; and the user node correspondingly transforms the received signal photons according to the Bell state measurement result to obtain the quantum state sent by the opposite party, thereby realizing duplex quantum teleportation. According to the invention, quantum stealth transmission in two directions can be realized at the same time under the condition of not increasing extra quantum channels.

Description

A duplex quantum teleportation device Technical Field

[0001] This invention belongs to the field of quantum information science and technology, specifically relating to a duplex quantum teleportation device. Background Technology

[0002] Developing quantum entangled interconnection schemes is a crucial step in advancing the global quantum internet. As a core technology in quantum entangled interconnection systems, quantum teleportation enables the reliable transfer of quantum information from one location to another without directly transmitting the quantum state itself. Current quantum teleportation is typically a one-way process: the sender performs a Bell state measurement on the unknown quantum state to be transmitted and its entangled photons, and sends the measurement result to the receiver via a classical channel; the receiver then performs corresponding operations based on the received classical information to reconstruct the unknown quantum state locally. Therefore, quantum teleportation is widely considered one of the key technological pathways for building long-distance, large-scale quantum networks and realizing the quantum internet.

[0003] The traditional method for one-way quantum teleportation involves a device comprising: a quantum entangled light source, a Bell state measurement module (BSM), a quantum information transmission module, a quantum information reception module, a classical channel, and a quantum channel. The quantum entangled light source generates entangled photons—idle photons and signal photons—which are distributed to the Bell state measurement module and the quantum information reception module, respectively. The quantum state transmitted by the quantum information transmission module is compared with the idle photons to perform Bell state measurements, and each Bell state measurement event is recorded using a single-photon detector and a time-to-digital converter. The measurement result is transmitted to the quantum information reception module via the classical channel. The quantum information reception module then transforms the received signal photon according to the Bell state measurement result to obtain the transmitted quantum state.

[0004] However, traditional one-way quantum teleportation still has certain limitations in terms of communication direction, parallelism, and quantum resource utilization efficiency. Duplex quantum teleportation, on the other hand, refers to the simultaneous transmission of quantum information in two directions, where the sender transmits an unknown quantum state to the receiver while the receiver simultaneously transmits another unknown quantum state back to the sender. Compared to one-way quantum teleportation, duplex quantum teleportation significantly improves the communication efficiency and parallelism between quantum network nodes, saving quantum channel and entanglement resources while increasing system resource utilization. This technology provides crucial support for efficient quantum information exchange between multiple nodes in the future quantum internet and is one of the fundamental technologies for building large-scale, high-efficiency quantum information networks. Summary of the Invention

[0005] To address the shortcomings of traditional simplex quantum teleportation systems, this invention proposes a duplex quantum teleportation device.

[0006] The technical solution of this invention is:

[0007] A duplex quantum teleportation device is characterized by comprising a first user node, a second user node, and a server node. The server node is connected to the first user node and the second user node via a quantum channel and a classical channel, respectively. The quantum channel is used to transmit quantum states and entangled photons, and the classical channel is used to transmit Bell state measurement results.

[0008] The first user node and the second user node each have a quantum information transmission module and a quantum information reception module. The quantum information transmission module is used to generate, convert, encode, or externally input quantum information to be transmitted. The quantum information reception module recovers the transmitted quantum state based on the Bell state measurement results.

[0009] The server node receives quantum information sent by the first user node and the second user node through a quantum channel and performs Bell state measurements. Then, the server node records each Bell state measurement event and sends it to the first user node and the second user node through a classical channel. At the same time, it distributes the signal photon corresponding to the idler photon to the first user node and the second user node. The first user node and the second user node transform the received signal photon according to the Bell state measurement result to obtain the quantum state sent by the other party, realizing duplex quantum teleportation.

[0010] Furthermore, the quantum information transmission module includes a circulator 24, a first arbitrary waveform generator 25, a first microwave amplifier 26, a first continuous laser source 27, a first intensity modulator 28, a first tunable optical attenuator 29, a second unequal-arm Mach-Zehnder interferometer 30, and a first dense wavelength division multiplexer 31; wherein, the first continuous laser source 27, the first intensity modulator 28, the first tunable optical attenuator 29, the second unequal-arm Mach-Zehnder interferometer 30, and the first dense wavelength division multiplexer 31 are cascaded in sequence, the first arbitrary waveform generator 25 is used to generate the required radio frequency pulses and send them to the first microwave amplifier 26, the first microwave amplifier 26 amplifies the voltage of the received radio frequency pulses and then sends them to the first intensity modulator 28 to modulate the laser, and the output terminal of the first dense wavelength division multiplexer 31 is connected to the first port of the circulator 24;

[0011] The quantum information receiving module includes a first time-to-digital converter 19, a first single-photon detector 20, a first polarization controller 21, a second polarization controller 22, and a first unequal-arm Mach-Zehnder interferometer 23. The input of the first unequal-arm Mach-Zehnder interferometer 23 is connected to the second port of a circulator 24. The two outputs of the first unequal-arm Mach-Zehnder interferometer 23 are connected to the first single-photon detector 20 via the first polarization controller 21 and the second polarization controller 22, respectively. The first single-photon detector 20 has dual channels, and the outputs of the two channels are connected to the first time-to-digital converter 19, which records the arrival time of the photons.

[0012] The third port of circulator 24 is used to send quantum information generated by the quantum information sending module or to receive signals sent by the server node.

[0013] Furthermore, the server node performs Bell state measurements via a Bell state measurement module, which includes a third polarization controller 32, a fourth polarization controller 33, a first polarization beamsplitter 34, a second polarization beamsplitter 35, a first polarization-maintaining beamsplitter 36, a third polarization controller 37, a fifth polarization controller 38, a second single-photon detector 39, and a second time-to-digital converter 40. The third polarization controller 32 and the first polarization beamsplitter 34, the fourth polarization controller 33, and the second polarization beamsplitter 35 are connected to form two signal receiving paths, with photons in both paths exhibiting identical polarization directions. The signals from both receiving paths, after passing through the first polarization-maintaining beamsplitter 36, are output to the second single-photon detector 39 via the third polarization controller 37 and the fifth polarization controller 38, respectively. The second single-photon detector 39 has dual channels, and the outputs of both channels are connected to the second time-to-digital converter 40. The second time-to-digital converter 40 records the photon arrival time and performs coincidence measurements, thus realizing Bell state measurements.

[0014] Furthermore, the server node generates idler photons through a space-division multiplexing quantum light source module. This module includes a second arbitrary waveform generator 41, a second microwave amplifier 42, a second continuous laser source 43, a second intensity modulator 44, an erbium-doped fiber amplifier 45, a second tunable optical attenuator 46, a sixth polarization controller 47, a second polarization-maintaining beam splitter 48, a second dense wavelength division multiplexer 49, a quantum light source 50, and a third dense wavelength division multiplexer 51. The second continuous laser source 43, the second intensity modulator 44, the erbium-doped fiber amplifier 45, the second tunable optical attenuator 46, the sixth polarization controller 47, and the second polarization-maintaining beam splitter 48 are cascaded sequentially. The second arbitrary waveform generator 41 is used to generate the required... The radio frequency pulse is sent to the second microwave amplifier 42, which amplifies the voltage of the received radio frequency pulse to the half-wave voltage of the second intensity modulator 44, and then sends it to the second intensity modulator 44 to modulate the laser. The second intensity modulator 44 and the erbium-doped fiber amplifier 45 modulate the laser to obtain a double-pulse pump light with a period and pulse width consistent with the time slice qubits transmitted in the quantum information transmission module. The two outputs of the second polarization-maintaining beam splitter 48 are respectively connected to the second dense wavelength division multiplexer 49 and the third dense wavelength division multiplexer 51. The second dense wavelength division multiplexer 49 and the third dense wavelength division multiplexer 51 are connected to the quantum light source 50, where entangled photon pairs are generated to obtain the required idler photons and signal photons.

[0015] The beneficial effect of this invention is that it can simultaneously achieve quantum teleportation in two directions without adding an additional quantum channel. Attached Figure Description

[0016] Figure 1 is a schematic diagram of the structure of a duplex quantum teleportation method and device according to the present invention;

[0017] Figure 2 is a schematic diagram of different architectures of duplex quantum teleportation according to the present invention;

[0018] Figure 3 is a diagram of the user node—quantum information transmission module and quantum information reception module—in an embodiment of the present invention.

[0019] Figure 4 is a diagram of the Bell state measurement module according to an embodiment of the present invention;

[0020] Figure 5 is a diagram of the quantum light source module according to an embodiment of the present invention;

[0021] Figure 6 shows the test results of the forward equatorial quantum state coherence transfer in an embodiment of the present invention;

[0022] Figure 7 shows the test results of the reverse equatorial quantum state coherence transfer in an embodiment of the present invention;

[0023] The attached diagram lists the components represented by each number as follows:

[0024] User 1, Server 2, User 3, First User Node 4, First Server Node 5, Second User Node 6, Third User Node 7, Second Server Node 8, Fourth User Node 9, Fifth User Node 10, Third Server Node 11, Sixth User Node 12, Seventh User Node 13, Fourth Server Node 14, Eighth User Node 15, Ninth User Node 16, Fifth Server Node 17, Tenth User Node 18, First Time-to-Digital Converter 19, First Single-Photon Detector 20, First Polarization Controller 21, Second Polarization Controller 22, First Unequal-Arm Mach-Zehnder Interferometer 23, Circulator 24, First Arbitrary Waveform Generator 25, First Microwave Amplifier 26, First Continuous Laser Source 27, First Intensity Modulator 28. First tunable optical attenuator; 29. ​​Second unequal-arm Mach-Zehnder interferometer; 30. First dense wavelength division multiplexer; 31. Third polarization controller; 32. Fourth polarization controller; 33. First polarization beamsplitter; 34. Second polarization beamsplitter; 35. First polarization-maintaining beamsplitter; 36. Third polarization controller; 37. Fifth polarization controller; 38. Second single-photon detector; 39. Second time-to-digital converter; 40. Second arbitrary waveform generator; 41. Second microwave amplifier; 42. Second continuous laser source; 43. Second intensity modulator; 44. Erbium-doped fiber amplifier; 45. Second tunable optical attenuator; 46. Sixth polarization controller; 47. Second polarization-maintaining beamsplitter; 48. Second dense wavelength division multiplexer; 49. Quantum light source; 50. Third dense wavelength division multiplexer; 51. Detailed Implementation

[0025] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present invention and are not configured to limit the present invention. For those skilled in the art, the present invention can be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present invention by illustrating examples of the invention.

[0026] The duplex quantum teleportation device of the present invention includes a first user node, comprising a first quantum information transmitting module and a first quantum information receiving module; a second user node, comprising a second quantum information transmitting module and a second quantum information receiving module; a server node, used to provide quantum entanglement sources and Bell state measurement services for two quantum teleportation directions; a quantum channel, connecting the first user node, the second user node, and the functional service node, used to transmit quantum states and entangled photons; and a classical channel, used to transmit Bell state measurement results between nodes.

[0027] The connection between duplex quantum teleportation nodes is shown in Figure 1. User 1 and User 3 can send quantum information to be transmitted to Server 2. Server 2 performs Bell state measurements on the quantum states and idler photons sent by the two user nodes, respectively. Each Bell state measurement event is recorded using a single-photon detector and a time-to-digital converter, and then transmitted to the two users via a classical channel. Simultaneously, the server distributes the signal photons corresponding to the idler photons to the two users. Based on the Bell state measurement results, the two users transform the received signal photons accordingly to obtain the quantum state sent by the other party. By centralizing the Bell state measurement module and the quantum light source module on the server, as shown in the first server node 5 in Figure 2, this architecture has low hardware requirements for users and is a scalable quantum teleportation network structure.

[0028] As shown in Figure 2, this invention can realize duplex quantum teleportation with different architectures according to requirements. This is mainly manifested in the transfer of server functional modules to the user side as needed. It is worth noting that the functionality of the modules, i.e., the role of different modules in the duplex quantum teleportation process, remains unchanged. Other duplex quantum teleportation architectures are described below.

[0029] As shown in Figure 2, the third user node 7, the second server node 8, and the fourth user node 9 constitute a full-duplex quantum teleportation system. The third user node 7 includes a quantum information transmission module and a quantum information reception module; the second server node 8 includes two different Bell state measurement modules and a quantum light source module; and the fourth user node 9 includes a quantum information transmission module and a quantum information reception module. Optionally, the quantum information nodes are connected via single-mode optical fibers of different lengths to complete the connection of the full-duplex quantum teleportation channel link.

[0030] The fifth user node 10, the third server node 11, and the sixth user node 12 constitute a duplex quantum teleportation system. Unlike the systems described above, in this system, the five user nodes 10 and 12 prepare the qubits locally and perform Bell state measurements on the entangled photons distributed by the third server node 11. They then send the Bell state measurement results to each other to complete the duplex quantum teleportation. This network structure is suitable for scenarios where long-distance transmission of qubits carrying quantum states is difficult, requiring local Bell state measurements. The ninth user node 10, the fifth server node 11, and the tenth user node 12 follow a similar approach.

[0031] The seventh user node 13, the fourth server node 14, and the eighth user node 15 constitute a duplex quantum teleportation system. Unlike the aforementioned systems, the intermediate node, the fourth server node 14, is responsible for the network structure that performs Bell state measurements. The seven user nodes 13 and 15, the communicating parties in the quantum teleportation, need to prepare qubits and entangled photon pairs locally. They then send the corresponding photons (qubits or entangled photons) to the intermediate node, the fourth server node 14, as needed (i.e., to send or receive quantum states) for Bell state measurements, and finally complete the quantum teleportation process based on the Bell state measurement results.

[0032] Example:

[0033] This example demonstrates a duplex quantum teleportation device based on a space-division multiplexing quantum light source, comprising a first user node 1, a first server node 2, and a second user node 3. The first user node 1 includes a quantum information transmission module and a quantum information reception module; the first server node 2 includes a Bell state measurement module and a quantum entanglement source module; and the second user node 3 includes a quantum information transmission module and a quantum information reception module. The users and the server are connected and transmit quantum information via a quantum channel, while the server transmits the Bell state measurement results to the other two user nodes via a classical channel.

[0034] As shown in Figure 3, the quantum information transmitting module and quantum information receiving module provided in this embodiment are connected by a circulator 24. The quantum information transmitting module generates, converts, encodes, or externally inputs quantum information to be transmitted; the quantum information receiving module recovers the quantum information transmitted by another user node based on the Bell state measurement results. In this embodiment, the quantum information transmitting module designs and implements the preparation of time-slice qubits and transmits them to server node 2. The quantum information transmitting module includes a circulator 24, a first arbitrary waveform generator (AWG) 25, a first microwave amplifier 26, a first continuous laser source 27, a first intensity modulator 28, a first tunable optical attenuator 29, a second unequal-arm Mach-Zehnder interferometer 30, and a first dense wavelength division multiplexer 31, with each component connected as shown in Figure 3. The circulator 24 is used to control the direction of the optical path. A first arbitrary waveform generator 25 generates radio frequency pulses with a repetition rate of 500 MHz and a pulse width of 60 ps. It can also be synchronized with other devices, such as time-to-digital converters (TDCs), via classical channel connections. A first microwave amplifier 26 amplifies the voltage of this pulse to reach the half-wave voltage of the intensity modulator used. A first continuous laser 27 has a wavelength set to 1549.32 nm. A first intensity modulator 28 modulates the continuous laser into a coherent optical pulse sequence, which is then attenuated to a single-photon level photon wave packet by a first adjustable optical attenuator 29. A second unequal-arm Mach-Zehnder interferometer 30 divides the coherent photon wave packet into time-slice photon wave packets passing through a long arm and a short arm. By fine-tuning the length of the long arm, the phase between the preceding and following wave packets is changed, enabling the fabrication of arbitrary superposition state qubits. A first dense wavelength division multiplexer 31 performs frequency domain filtering on the time-slice qubits to ensure the indistinguishability of photons in Bell state measurements. The quantum information receiving module includes a first time-to-digital converter 19, a first single-photon detector 20, a first polarization controller 21, a second polarization controller 22, and a first unequal-arm Mach-Zehnder interferometer 23, all connected as shown in Figure 3. The arm length difference of the first unequal-arm Mach-Zehnder interferometer 23 is consistent with the time-slice photon wave packet, allowing adjustment of the time-slice qubits after phase detection and transmission. The first single-photon detector 20 is a dual-channel superconducting nanowire single-photon detector. Because the selected superconducting nanowire single-photon detector is polarization-sensitive, a polarization controller is used in conjunction with it. The first single-photon detector 20 uses two channels, which are connected to the first time-to-digital converter 19 via radio frequency cables to record the arrival time of photons.

[0035] As shown in Figure 4, the Bell state measurement module in server node 2 provided in this embodiment receives quantum information (carried by time-slice qubits) and idler photons generated by the quantum entanglement source module from two directions, namely the first user node 1 and the second user node 3. It performs Bell state measurement processing, records the Bell state measurement results, and sends them to the quantum information receiving modules in the first user node 1 and the second user node 3 respectively through classical channels to recover the transmitted quantum information, thus realizing duplex quantum teleportation. It includes a third polarization controller 32, a fourth polarization controller 33, a first polarization beamsplitter 34, a second polarization beamsplitter 35, a first polarization-maintaining beamsplitter 36, a third polarization controller 37, a fifth polarization controller 38, a second single-photon detector 39, and a second time-to-digital converter 40. These components are connected as shown in Figure 4. The third polarization controller 32, the fourth polarization controller 33, the first polarization beamsplitter 34, and the second polarization beamsplitter 35 ensure that the polarization directions of the two photons are identical during Bell state measurement. The second single-photon detector 39 is a superconducting nanowire single-photon detector with sensitive polarization direction, so it is used in conjunction with a polarization controller. The second single-photon detector 39 uses two channels, which are connected to the second digital time converter 40 via radio frequency cables to record the arrival time of photons and perform coincidence measurements to realize Bell state measurements.

[0036] As shown in Figure 5, the space-division multiplexing quantum light source module in server node 2 provided in this embodiment can generate quantum entanglement using quantum dots or nonlinear effects. For example, the selected quantum light source module generates quantum entanglement through a second-order nonlinear effect. Specifically, the design involves cascading second harmonic frequency doubling and spontaneous parametric down-conversion processes in a periodically polarized lithium niobate waveguide to generate energy-time entanglement. It includes a second arbitrary waveform generator 41, a second microwave amplifier 42, a second continuous laser light source 43, a second intensity modulator 44, an erbium-doped fiber amplifier 45, a second tunable optical attenuator 46, a sixth polarization controller 47, a second polarization-maintaining beam splitter 48, a second dense wavelength division multiplexer 49, a quantum light source 50, and a third dense wavelength division multiplexer 51. The second arbitrary waveform generator 41 is used to generate a radio frequency double pulse with a repetition rate of 500MHz, a pulse width of 60ps, and an interval of 625ps. The second microwave amplifier 42 is used to amplify the voltage of this pulse to reach the half-wave voltage of the intensity modulator used. The second continuous laser source 43, the second intensity modulator 44, and the erbium-doped fiber amplifier 45 modulate the dual-pulse pump light, with the period and pulse width consistent with the time-slice qubits transmitted in the quantum information transmission module. The pump light generates entangled photon pairs in the quantum source 50—a periodically polarized lithium niobate waveguide module—based on cascaded second harmonic doubling and spontaneous parametric down-conversion. A sixth polarization controller 47 is required to calibrate the input pump light with a center wavelength of 1540.56 nm. Subsequently, the light is filtered by the second dense wavelength division multiplexer 49 and the third dense wavelength division multiplexer 51, separating the idler photon with a bandwidth of approximately 12 GHz and a center wavelength of 1549.32 nm from the signal photon with a wavelength of 1531.92 nm.

[0037] As shown in Figures 6 and 7, this embodiment initially detects the fidelity of the equatorial quantum state in a time-slice qubit using a coherence transfer method, verifying the effectiveness and feasibility of duplex quantum teleportation based on a space-division multiplexed quantum light source. By scanning the phase of the unequal-arm Mach-Zehnder interferometer, the experiment measured the triple coincidence counts of the two output ports of the interferometer with the double coincidence count results of the Bell state measurement, as shown by the experimental data points on the two sinusoidal curves in Figures 6 (7). The cumulative measurement time for each phase is 60 seconds. By fitting the interference curve using the Monte Carlo method, the interference visibility V was 40.2±1.9% and 45.3±2.2% (42.2±1.8% and 42.7±2.3%), with an average of 42.8±2.0% (42.5±2.2%). According to the formula F=(1+V) / 2, the equatorial quantum state fidelity was calculated to be 71.4±2.0% (71.2±2.2%), which exceeds the classical limit. This indicates that this embodiment initially achieved good quantum coherence transfer through the coherence transfer method, and can effectively transmit quantum information with high fidelity.

[0038] The time-slice qubits used in this embodiment are merely a common carrier of quantum information, intended to facilitate implementation and understanding. Those skilled in the art can easily transfer these methods and modules to other quantum information encoding methods and modules, such as polarizer qubits and high-dimensional encoding, or to quantum teleportation system modules with hollow-core fiber connections and different topologies. These systems, methods, and modules are widely applicable to quantum networks.

Claims

1. A duplex quantum teleportation device, characterized in that, The system comprises a first user node, a second user node, and a server node. The server node is connected to the first and second user nodes via a quantum channel and a classical channel, respectively. The quantum channel is used to transmit quantum states and entangled photons, while the classical channel is used to transmit Bell state measurement results. Each of the first and second user nodes has a quantum information transmitting module and a quantum information receiving module. The quantum information transmitting module generates, converts, encodes, or externally inputs quantum information to be transmitted. The quantum information receiving module recovers the transmitted quantum state based on the Bell state measurement results. The server node receives the quantum information transmitted by the first and second user nodes via the quantum channel and performs Bell state measurements. The server node then records each Bell state measurement event and transmits it to the first and second user nodes via the classical channel, while simultaneously distributing the signal photon corresponding to the idler photon to both user nodes. The first and second user nodes transform the received signal photon according to the Bell state measurement results to obtain the quantum state transmitted by the other party, thus achieving full-duplex quantum teleportation.

2. The duplex quantum teleportation device according to claim 1, characterized in that, The quantum information transmission module includes a circulator (24), a first arbitrary waveform generator (25), a first microwave amplifier (26), a first continuous laser source (27), a first intensity modulator (28), a first tunable optical attenuator (29), a second unequal-arm Mach-Zehnder interferometer (30), and a first dense wavelength division multiplexer (31). The first continuous laser source (27), the first intensity modulator (28), the first tunable optical attenuator (29), the second unequal-arm Mach-Zehnder interferometer (30), and the first dense wavelength division multiplexer (31) are cascaded in sequence. The first arbitrary waveform generator (25) generates the required radio frequency pulses and sends them to the first microwave amplifier (26). The first microwave amplifier (26) amplifies the voltage of the received radio frequency pulses and then sends them to the first intensity modulator (28) to modulate the laser. The output of the first dense wavelength division multiplexer (31) is connected to the circulator (24). The first port of the quantum information receiving module includes a first time-to-digital converter (19), a first single-photon detector (20), a first polarization controller (21), a second polarization controller (22), and a first unequal-arm Mach-Zehnder interferometer (23). The input of the first unequal-arm Mach-Zehnder interferometer (23) is connected to the second port of the circulator (24), and the two outputs of the first unequal-arm Mach-Zehnder interferometer (23) are connected to the first single-photon detector (20) through the first polarization controller (21) and the second polarization controller (22), respectively. The first single-photon detector (20) has two channels, and the outputs of the two channels are connected to the first time-to-digital converter (19). The first time-to-digital converter (19) records the arrival time of the photon. The third port of the circulator (24) is used to send quantum information generated by the quantum information sending module or to receive signals sent by the server node.

3. A duplex quantum teleportation device according to claim 1 or 2, characterized in that, The server node performs Bell state measurements through a Bell state measurement module, which includes a third polarization controller (32), a fourth polarization controller (33), a first polarization beamsplitter (34), a second polarization beamsplitter (35), a first polarization-maintaining beamsplitter (36), a third polarization controller (37), a fifth polarization controller (38), a second single-photon detector (39), and a second time-to-digital converter (40). The third polarization controller (32), the first polarization beamsplitter (34), the fourth polarization controller (33), and the second polarization beamsplitter (35) are connected to form two signal receiving paths, and the polarization directions of the photons in the two signal receiving paths are exactly the same. The signals in the two signal receiving paths are output to the second single-photon detector (39) after passing through the first polarization-maintaining beamsplitter (36) and the third polarization controller (37) and the fifth polarization controller (38), respectively. The second single-photon detector (39) has two channels, and the outputs of the two channels are connected to the second time-to-digital converter (40). The second time-to-digital converter (40) records the arrival time of the photons and performs coincidence measurements to realize Bell state measurements.

4. The duplex quantum teleportation device according to claim 3, characterized in that, The server node generates idler photons through a space-division multiplexing quantum light source module. The space-division multiplexing quantum light source module includes a second arbitrary waveform generator (41), a second microwave amplifier (42), a second continuous laser source (43), a second intensity modulator (44), an erbium-doped fiber amplifier (45), a second tunable optical attenuator (46), a sixth polarization controller (47), a second polarization-maintaining beam splitter (48), a second dense wavelength division multiplexer (49), a quantum light source (50), and a third dense wavelength division multiplexer (51). The second continuous laser source (43), second intensity modulator (44), erbium-doped fiber amplifier (45), second tunable optical attenuator (46), sixth polarization controller (47), and second polarization-maintaining beam splitter (48) are cascaded sequentially. The second arbitrary waveform generator (41) is used to generate… The required radio frequency pulse is sent to the second microwave amplifier (42). The second microwave amplifier (42) amplifies the voltage of the received radio frequency pulse to the half-wave voltage of the second intensity modulator (44), and then sends it to the second intensity modulator (44) to modulate the laser. The second intensity modulator (44) and the erbium-doped fiber amplifier (45) modulate the laser to obtain a double-pulse pump light. The period and pulse width are consistent with the time slice qubits sent in the quantum information transmission module. The two outputs of the second polarization-maintaining beam splitter (48) are connected to the second dense wavelength division multiplexer (49) and the third dense wavelength division multiplexer (51) respectively. The second dense wavelength division multiplexer (49) and the third dense wavelength division multiplexer (51) are connected to the quantum light source (50). Entangled photon pairs are generated in the quantum light source (50) to obtain the required idler photon and signal photon.

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